Invert DSF to map from delegated frame to layer space

content/browser/renderer_host/render_widget_host_view_android.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_android.h"
 
 #include <android/bitmap.h>
 
 #include "base/android/sys_utils.h"
 #include "base/basictypes.h"
@@ skipping 670 matching lines @@
   scoped_ptr<cc::CopyOutputRequest> request;
   scoped_refptr<cc::Layer> readback_layer;
   DCHECK(content_view_core_);
   DCHECK(content_view_core_->GetWindowAndroid());
   ui::WindowAndroidCompositor* compositor =
       content_view_core_->GetWindowAndroid()->GetCompositor();
   DCHECK(compositor);
   DCHECK(frame_provider_);
   scoped_refptr<cc::DelegatedRendererLayer> delegated_layer =
       cc::DelegatedRendererLayer::Create(frame_provider_);
-  delegated_layer->SetDisplaySize(texture_size_in_layer_);
   delegated_layer->SetBounds(content_size_in_layer_);
   delegated_layer->SetHideLayerAndSubtree(true);
   delegated_layer->SetIsDrawable(true);
   delegated_layer->SetContentsOpaque(true);
+  gfx::Transform layer_scale(
+      device_scale_factor, 0.f, 0.f, device_scale_factor, 0.f, 0.f);
+  delegated_layer->SetTransform(layer_scale);
   compositor->AttachLayerForReadback(delegated_layer);
 
   readback_layer = delegated_layer;
   request = cc::CopyOutputRequest::CreateRequest(
       base::Bind(&RenderWidgetHostViewAndroid::
                      PrepareTextureCopyOutputResultForDelegatedReadback,
                  dst_size_in_pixel,
                  bitmap_config,
                  start_time,
                  readback_layer,
@@ skipping 99 matching lines @@
       frame_provider_ = new cc::DelegatedFrameProvider(
           resource_collection_.get(), frame_data.Pass());
       layer_ = cc::DelegatedRendererLayer::Create(frame_provider_);
       AttachLayers();
     } else {
       frame_provider_->SetFrameData(frame_data.Pass());
     }
   }
 
   if (layer_.get()) {
-    layer_->SetDisplaySize(texture_size_in_layer_);
     layer_->SetIsDrawable(true);
     layer_->SetContentsOpaque(true);
     layer_->SetBounds(content_size_in_layer_);
     layer_->SetNeedsDisplay();
+    // DelegatedRendererLayer scales the frame data from physical space to DIPs
+    // by inverting the frame's device scale factor, assuming that the browser
+    // compositor will map from DIPs back to physical pixels using its own
+    // device scale factor. However, the Android browser compositor always uses
+    // a device scale factor of 1.0, so we have to transform the delegated
+    // layer by the device scale to get it into the same physical pixel space as
+    // the rest of the UI.
+    const gfx::Display& display =
+        gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
+    float device_scale_factor = display.device_scale_factor();
+    gfx::Transform layer_scale(
+        device_scale_factor, 0.f, 0.f, device_scale_factor, 0.f, 0.f);
+    layer_->SetTransform(layer_scale);
   }
 
   base::Closure ack_callback =
       base::Bind(&RenderWidgetHostViewAndroid::SendDelegatedFrameAck,
                  weak_ptr_factory_.GetWeakPtr(),
                  output_surface_id);
 
   ack_callbacks_.push(ack_callback);
   if (host_->is_hidden())
     RunAckCallbacks();
@@ skipping 610 matching lines @@
   results->availableRect = display.work_area();
   results->deviceScaleFactor = display.device_scale_factor();
   results->orientationAngle = display.RotationAsDegree();
   gfx::DeviceDisplayInfo info;
   results->depth = info.GetBitsPerPixel();
   results->depthPerComponent = info.GetBitsPerComponent();
   results->isMonochrome = (results->depthPerComponent == 0);
 }
 
 } // namespace content